Assessment of Regional Spatiotemporal Variations in Drought from the Perspective of Soil Moisture in Guangxi, China

Abstract

Understanding the changes in regional droughts is important for promoting overall sustainable development. However, the spatiotemporal dynamics of soil droughts in Guangxi under the background of global warming and regional vegetation restoration have not been studied extensively, and the potential causes are scarcely understood. Here, using TerraClimate soil moisture data, we constructed a monthly standardized soil moisture index (SSMI), analyzed the seasonal and annual spatiotemporal distribution of droughts from the perspective of soil moisture, and studied past soil drought events in Guangxi. Migration methods of drought centroid, trend analysis, and principal component decomposition were used. In the interannual dynamics, the overall SSMI increased, indicating that the soil drought situation was gradually alleviated in Guangxi. Further, the frequency of extreme and severe droughts decreased with time, mainly in autumn and winter. During early drought stages, the migration path was short, which extended as the droughts progressed. Ocean temperature and soil moisture were strongly correlated, indicating that abnormal ocean surface temperature may drive soil moisture. This study provides scientific guidance for the early warning, prevention, and mitigation of losses associated with soil droughts in Guangxi and serves as valuable reference for understanding the impacts of large-scale climate anomalies on soil moisture.

Assessing Drought, Flood, and High Temperature Disasters during Sugarcane Growth Stages in Southern China

“…In terms of the sugarcane growth stages, the stem elongation stage was found to be the period during which sugarcane drought and flood were most intensive in a year. A similar finding was observed in another study on soil droughts in Guangxi [44]; that report indicated that soil droughts occurred frequently during autumn and winter seasons in Guangxi, which mainly corresponded to the stem elongation stage. However, when the influences of growth stage length were considered, the mature stage had the greatest probability of drought and flood occurrence per month; by contrast, the tillering stage had the minimum probability, which has been reported in a relevant study that focused on sugarcane drought in Guangxi [25].…”

Monitoring of Extreme Agricultural Drought of the Past 20 Years in Southwest China Using GLDAS Soil Moisture

“…The SMI is defined as the percentage of actual soil moisture in the field capacity, reflecting the relative dryness of the soil. The SMI can be used to detect droughts in specific soil types in small-scale areas, but it has limitations [65]. Although the VSWI monitoring method is intuitive, it is easily affected by cloud and vegetation conditions.…”